diff options
| author | Hugh Dickins <hughd@google.com> | 2017-11-04 18:43:06 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-05 15:46:35 +0100 |
| commit | fe5cb75fd2dd51746fd391c7f6d18485e6a44f76 (patch) | |
| tree | 3d39e1642a191df61177da5eec32c20f683d2294 /arch/x86/mm/tlb.c | |
| parent | b72c26e911c566c78743d7973103925007d103c7 (diff) | |
kaiser: kaiser_flush_tlb_on_return_to_user() check PCID
Let kaiser_flush_tlb_on_return_to_user() do the X86_FEATURE_PCID
check, instead of each caller doing it inline first: nobody needs
to optimize for the noPCID case, it's clearer this way, and better
suits later changes. Replace those no-op X86_CR3_PCID_KERN_FLUSH lines
by a BUILD_BUG_ON() in load_new_mm_cr3(), in case something changes.
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/mm/tlb.c')
| -rw-r--r-- | arch/x86/mm/tlb.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index e7934aed8d67..41205de487e7 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -39,7 +39,7 @@ static void load_new_mm_cr3(pgd_t *pgdir) { unsigned long new_mm_cr3 = __pa(pgdir); - if (kaiser_enabled && this_cpu_has(X86_FEATURE_PCID)) { + if (kaiser_enabled) { /* * We reuse the same PCID for different tasks, so we must * flush all the entries for the PCID out when we change tasks. @@ -50,10 +50,10 @@ static void load_new_mm_cr3(pgd_t *pgdir) * do it here, but can only be used if X86_FEATURE_INVPCID is * available - and many machines support pcid without invpcid. * - * The line below is a no-op: X86_CR3_PCID_KERN_FLUSH is now 0; - * but keep that line in there in case something changes. + * If X86_CR3_PCID_KERN_FLUSH actually added something, then it + * would be needed in the write_cr3() below - if PCIDs enabled. */ - new_mm_cr3 |= X86_CR3_PCID_KERN_FLUSH; + BUILD_BUG_ON(X86_CR3_PCID_KERN_FLUSH); kaiser_flush_tlb_on_return_to_user(); } |